Coastal Flood Management Global Innovations Tuesday, 13 December 2005

Global Innovative Flood Control Barriers Protecting people, property and environment Arjan van der Weck WL | Delft Hydraulics

Topics Large European Flood Control Barriers Background Facts and figures Operational, under construction or in planning phase Concluding remarks

Flood Protection Barriers covered Eastern Scheldt Storm Surge Barrier, The Netherlands Maeslant Barrier, Rotterdam, The Netherlands Water Control Gates, Venice, Italy St. Petersburg Flood Protection Barrier, Russia Thames Barrier, London, United Kingdom

Sea Barrier Structures, The Netherlands Netherlands: below sea-level in Rhine and Meuse delta 1953: storm surge floods south-western part of the Netherlands Highly traumatic experience, main lessons: do not forget, but to be aware and be prepared Option chosen: shorten line of defence!

Eastern Scheldt Barrier, The Netherlands 1954: Full closure plan of Eastern Scheldt inlet, closed coastline to protect the southwestern part of Holland and Zeeland from flood threats 1975: Pressure from fishing, oyster and mussel culture and increased environmental awareness, plans for closure changed 1987: commissioning of the barrier Years ’90: extensive monitoring and evaluation Leading to changing views on functioning and purpose…

Eastern Scheldt Barrier, The Netherlands Facts and figures Costs 8.7 billion $ US (price level 2005) Protection level, return period 1:4,000 years Protecting roughly 100,000 people and large nature area Completed 1986 / 1987

Maeslant Barrier, Rotterdam, The Netherlands Facts and figures Closing off (parts of) one of the largest ports in the world Intensive shipping traffic Costs: $530M Protecting 1 million people and one of the largest industrial areas in Europe Protection level 1:10,000 Completed 1997

Maeslant Barrier, Rotterdam, The Netherlands Design and construct contract Design criteria included minimal protection against flooding minimal depth of shipping route minimal width of shipping route closure time (traffic interrupted) less than 1%, or once in 5 to 10 years no overhead constructions Design optimized using physical modeling techniques, reduction of vibration

Maeslant Barrier, Rotterdam, The Netherlands Ball joints designed to ensure movement of gates in all directions Ball joints transfer pressure of water on gates to foundation Three times bigger than ever used before! Operation of the barrier fully computerised, using Command and Support system

St. Petersburg Flood Protection Barrier, Russia St. Petersburg is situated just several feet above mean sea level in the Neva Delta has experienced many serious floodings throughout its history due to high water in the Gulf of Finland. with the present population a flood of 3m with a return period of 50 years could be catastrophic

St. Petersburg Flood Protection Barrier, Russia 1980: Start of construction of Flood Protection barrier (FPB): 1987: Suspension of construction due due to a huge environmental controversy and a lack of funding changing political and financial situation 2001: Feasibility study of FPB completion financed by Dutch government 2002: Series of studies financed by EBRD (WL leads EIA, contributes to TFS) 2008: Planned completion of FPB

St. Petersburg Flood Protection Barrier, Russia

Facts and figures length 23 kilometer, 6 movable flood gate complexes and 2 navigable openings protects 5 million people costs (for completion): $840 million (100% over budget) protection level, return period of 1:10,000 to be completed in 2008

Water Control Gates Venice, Italy situated in Venice Lagoon in Adriatic sea regular flooding is damaging the historic city Venice lagoon suffers from man-made interventions and pollution flooding risk increases due to sea level rise and soil subsidence

Water Control Gates Venice, Italy Some facts and figures mobile gates in the three inlets offshore breakwaters in front of the entrances costs: $5.30 billion ($2.7 billion was estimated in 2004)

Water Control Gates Venice, Italy: 1. In normal conditions, the floodgates lie on the seabed 2. When high tides are expected, compressed air is pumped into the gates, causing the gates to rise 3. Once raised the gates form a slanting barrier against the incoming tide The gates are 30 metres high and five metres thick

Water Control Gates Venice, Italy: Dutch expertise used for: Design of the movable barriers: nautical aspects and bed protection (scale models) Hydrodynamical, morphological and ecological modelling of the Venice lagoon (numerical models) Design of sluice complexes Study of the construction phases of the structures around the mobile gates

Thames Barrier, London, United Kingdom Facts and figures trigger: 1953 storm surge 1.25 million people at risk estimated damage figure for the tidal flooding of London of $140 billion (today) protection level 1:2,000 costs: $760 million (75% over budget, due to inflation in the 1970’s) barrier completed in 1982 closing 4 to 5 times / year courtesy UK Env. Agency

Thames Barrier, UK

Concluding remarks Major investments in flood protection are largely event driven Planning and design of the large flood protection works presented here usually started from a flood protection perspective only, ensuring protection for people and property Environmental aspects gained interest during planning and construction phase, often under considerable public pressure Some effects of new infrastructure are predictable, others are less or not predictable Continued monitoring and maintenance are therefore essential parts of the project

Meeting of barrier management groups Operational aspects barrier management are discussed between responsible authorities First meeting earlier this year in St. Petersburg, representatives of all barrier management authorities attended Next meeting in Venice, July 2007